Chile's constitutional court gave the green light on Thursday to Chinese group Tianqi's proposed acquisition of a 24 percent stake in Chile's lithium producer SQM for $4.1 billion.

The court rejected an appeal to halt the sale by SQM's controlling shareholder, the Pampa Group, which argued that such a deal would break competition rules as Tianqi also owns a stake in Albermarle, a direct competitor of SQM.

The court's president, Gonzalo Garcia, told reporters that the Pampa Group's challenge had been "declared inadmissible" by a split vote.

Pampa, which holds a 29.12 percent stake in SQM, had taken its challenge to the constitutional court after the industry's regulator approved the sale.

It said Tianqi's acquisition from Canadian Nutrien group, agreed in May, would allow "a market player to partially hold and participate in the management of one of its direct competitors."

Pampa -- made up of Pampa Calichera, Potasios de Chile and Global Mining -- added that such a deal would give a direct competitor "access to confidential and economically sensitive information on the global lithium market."

The deal potentially gives Tianqi influence over some 70 percent of the global lithium market, according to some estimates.

Prior to the case, Tianqi had described the constitutional court's approval of the deal was a mere "formality."

Chile has the world's largest reserves of lithium, and alongside Australia produces around 80 percent of total global production.

SQM operates one of the world's largest lithium mines on the Atacama salt flats in northern Chile, while US company Albermarle is the world's leading lithium producer.

Lithium is used in batteries, and is in high demand given the boom in the production of electric cars.